Her suspension will end on June 21, 2030, when the two-time grand slam finalist from the Czech Republic will be 30 years old.
The International Tennis Integrity Agency said on Monday Vondrousova did not submit a sample when notified by a doping control officer during an out-of-competition surprise test attempt at her home at around 8 pm on December 3.
Vondrousova said during a hearing that stress, poor mental health and concerns for her safety - she claimed the tester did not identity herself - had affected her decision making when she refused to submit a sample.
The tribunal also took testimony from the doping control officer and concluded the evidence offered "no compelling justification" for the test refusal.
"We recognise this is a significant ban," ITIA CEO Karen Moorhouse said.
"You can't have an anti-doping system where a player is in a better place by refusing to take a test than they would by taking a test and testing positive. So that feeds into the structure of the doping rules that provides for a starting point in the four-year ban for refusing to take a test."
The 26-year-old Vondrousova detailed her reaction to the missed test in an Instagram post in April.
"It is very tough for me to talk about this, but I want to be transparent with you about my mental health," Vondrousova said. "The recent doping control incident happened because I reached a breaking point after months of physical and mental stress."
Vondrousova became Wimbledon's first unseeded female champion when she beat Ons Jabeur in the 2023 final. She reached a career-high ranking of No. 6 that year. She also reached the French Open final in 2019, losing to Ash Barty.
Vondrousova has not competed since pulling out of the Adelaide International in January due to a shoulder injury.
with AP
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